The present invention relates to a sulfur hexafluoride high-tension circuit-breaker.
With such a circuit breaker, the pressure to which the circuit-breaker is filled at ambient temperature is of the order of a few bars (3 to 15 bars, for example).
When the outside temperature falls, the pressure inside the circuit-breaker also falls.
When the temperature reaches a certain lower threshold value, the gas begins to liquefy. As a result there is a reduction in the vapor pressure and a corresponding reduction in the quality of the insulation provided by the dielectric gas.